Thyroid-Like Follicular Renal Cell Carcinoma

**Semantic type:** Neoplastic Process

**Definition:** An extremely rare type of renal cell carcinoma that histologically resembles thyroid follicular neoplasms. It is a well-circumscribed mass, characterized by the presence of thyroid-like follicles that contain eosinophilic, colloid-like material. It is negative for thyroid transcription factor 1 (TTF-1) and thyroglobulin. The majority of the reported cases have a low-grade malignant potential. Rare cases with lymph nodes involvement and distant metastases have also been described.

**Synonyms:** - TLFCK - TLFRCC - Thyroid-Like Follicular Carcinoma of the Kidney